Atrial fibrillation in elderly patients after coronary artery bypass grafting; gender differences in outcome

To evaluate gender-related differences in preoperative risk factors, hospital events, especially atrial fibrillation (AF), and length of stay in elderly patients undergoing isolated coronary artery bypass grafting (CABG).

Prospectively collected data from consecutive patients undergoing isolated CABG in Tampere University Hospital between May 1999 and November 2000, in total 1131 patients.

We analysed 621 patients 65 years and older of whom 401 (65%) were male. When evaluating gender differences we found that the women were older (73 vs. 71 yrs, p<0.001) and significantly more often had hypertension (66% vs. 49%, p<0.001) and chronic heart insufficiency (11% vs. 4%, p=0.001). The NYHA classification of the women was worse (3.4 vs. 3.1, p<0.001) and in the angiographic data they had left main stenosis more often (31% vs. 21%, p=0.005) than the men. The women needed longer hospitalisation (19 vs. 15 days, p<0.001). There was no difference in the prevalence of postoperative AF between the genders, but in spite of that women had more postoperative strokes (6% vs. 3%, p=0.028) and also other major complications (29% vs. 19%, p=0.004) than the men. The 30-day mortality was higher in the female group (8% vs. 5%, p=0.06). We analysed preoperative risk factors and found that the females had a 1.6-fold risk for postoperative major complication after adjustment for age and other risk factors. In a logistic regression analysis age and the number of anastomoses emerged as independent predictors of AF in males, but in females we could not find any predictor for postoperative AF.

The women are older and have more comorbidities and risk factors at the time of CABG. They also have more postoperative complications, but not a significantly higher mortality. Importantly, the excess of morbidity remains after adjustment for age and underlying risk factors. There is no gender difference in the incidence of postoperative AF in the elderly population. However, it seems to occur independent of age in the women only.